1. Field of the Invention
The present invention generally relates to a vehicle cruise control system. More specifically, the present invention relates to a vehicle cruise control system that is configured to execute cruise control in such a manner that the vehicle equipped with the cruise control system travels in a target traveling state, e.g., such a state as following a preceding vehicle or traveling at a constant speed.
2. Background Information
Over the years many different cruise control systems have been proposed for executing such cruise control states as following a preceding vehicle at a prescribed following distance and traveling at a constant speed based on a preset vehicle speed.
Some of these cruise control systems are provided with a following distance detecting sensor, such as a laser radar, that serves to determine if a preceding vehicle or an obstacle exists and detect the distance to the preceding vehicle or obstacle from the vehicle in which the cruise control system is installed. Such cruise control systems then execute the cruise control based on the detection results of the following distance detecting device.
When cruise control is executed based on the detection results of a following distance detecting device, there are times when the accuracy of the following distance detecting device declines due to rain, snow, or the like. In order to avoid executing cruise control based on a detection signal from a following distance detecting device whose accuracy could possibly have declined, such cruise control systems are configured to estimate the degree of rain or snow based on the operating state of the wipers and abort the cruise control or take other precautionary measures when the estimation results indicate a degree of rain or snow that could compromise the accuracy of the following distance detecting device.
For example, consider a case in which the wipers are provided with the following operating modes: a high-speed continuous mode in which the wipers are moved at a high speed in a continuous manner; a low-speed continuous mode in which the wipers are moved at a low speed in a continuous manner; and an intermittent mode in which the wipers are moved intermittently. In such a case, the cruise control system can be configured such that when the wipers are operating in the high-speed continuous mode or the low-speed continuous mode, the system estimates that the quantity of rainfall or snowfall is comparatively large and that the accuracy of the following distance detecting device could be low. The system can also be configured to determine that the quantity of rainfall or snowfall is comparatively large when the wipers are operating in the intermittent mode with a short time interval setting. Thus, when control of the vehicle speed by the cruise control system is in progress, the cruise control is aborted if it is detected that the wipers are operating in high-speed continuous mode, low-speed continuous mode, or intermittent mode with a comparatively short time interval setting.
One example of such a cruise control system is disclosed in Japanese Laid-Open Patent Publication No. 10-081156
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved vehicle cruise control system. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.